Familial tyrosinaemia with eye and skin lesions. Presentation of two cases

Tyrosinemia type II: Mutation update, 11 novel mutations and description of 5 independent subjects with a novel founder mutation

BACKGROUND

Tyrosinemia type II, also known as Richner-Hanhart Syndrome, is an extremely rare autosomal recessive disorder, caused by mutations in the gene encoding hepatic cytosolic tyrosine aminotransferase, leading to the accumulation of tyrosine and its metabolites which cause ocular and skin lesions, that may be accompanied by neurological manifestations, mostly intellectual disability.

AIMS

To update disease-causing mutations and current clinical knowledge of the disease.

MATERIALS AND METHODS

Genetic and clinical information were obtained from a collection of both unreported and previously reported cases.

RESULTS

We report 106 families, represented by 143 individuals, carrying a total of 36 genetic variants, 11 of them not previously known to be associated with the disease. Variants include 3 large deletions, 21 non-synonymous and 5 nonsense amino-acid changes, 5 frameshifts and 2 splice variants. We also report 5 patients from Gran Canaria, representing the largest known group of unrelated families sharing the same P406L mutation.

CONCLUSIONS

Data analysis did not reveal a genotype-phenotype correlation, but stressed the need of early diagnosis: All patients improved the oculocutaneous lesions after dietary treatment but neurological symptoms prevailed. The discovery of founder mutations in isolated populations, and the benefits of early intervention, should increase diagnostic awareness in newborns.

Isolated corneal pseudodendrites as the initial manifestation of tyrosinemia type II in monozygotic twins

Fifteen-month-old twins presented with photophobia and bilateral corneal pseudodendrites, and tyrosinemia type II was suspected. Plasma tyrosine levels were elevated. After therapy with tyrosine-restricted diet, corneal lesions resolved. Bilateral pseudodendritic keratitis may be the initial or only manifestation of tyrosinemia type II.

Corneal lesion as the initial manifestation of tyrosinemia type II

Tyrosinemia type II (Richner-Hanhart syndrome) is a rare autosomal recessive disease with deficiency of tyrosine aminotransferase and subsequently increasing level of serum tyrosine. We report the case of a 2-year-old girl who was referred due to bilateral corneal lesions. Slit-lamp examination showed small granular white deposits arranged in a dendritic pattern in the superficial central cornea of both eyes. Physical examination revealed painful, non-pruritic, hyperkeratotic plaques on the soles, palms and fingertips. Mental evaluation demonstrated developmental delay for her age. Blood examination revealed serum tyrosine level to be 1868 microM (normal range, 30-110 microM), which decreased to 838 microM with 2-month diet on tyrosine and phenylalanine restriction. The corneal and skin lesions resolved completely. However, the corneal deposits recurred a month later as her mother failed to strictly control the diet because the little girl was losing weight and activity. With specific formula and adjusted diet regimen, the corneal lesions decreased again. Corneal pseudodendritic deposits may be the initial manifestation in patients with tyrosinemia type II. Early diagnosis and intervention with diet control are crucial for preventing permanent visual and developmental deficits. Corneal deposits can be one of the parameters in monitoring the efficacy of diet control.

Oculocutaneous tyrosinaemia or tyrosinaemia type 2: a case report

Oculo-cutaneous tyrosinaemia type II is an autosomal recessive disease due to an abnormality of tyrosine metabolism, probably because of a deficiency of cytoplasmic tyrosine aminotransferase. It presents as a varying association of focal palmoplantar keratosis, bilateral keratitis and mental retardation. Herein, we report an 8-year-old boy with palmoplantar hyperkeratosis with peripheral oozing and dendritic keratitis appearing after the skin lesions. There was no mental deterioration despite the long delay in diagnosis of the disorder. The diagnosis was confirmed by the presence of hypertyrosinaemia and the absence of hepatorenal lesion. The child exhibited a remarkable degree of improvement in the hyperkeratotic lesions and keratitis after the dietary modifications were instituted. In conclusion, chronic focal bullous palmoplantar hyperkeratosis along with keratitis should alert the clinician to screen for abnormal serum and/or urine tyrosine level. Awareness of the presenting signs and symptoms may speed up the diagnosis and initiation of a tyrosine and phenylalanine-restricted diet that is most efficient in improving the symptoms and preventing visual and cognitive impairment.

Tyrosinemia type II: nine cases of ocular signs and symptoms

PURPOSE

To report nine cases of tyrosinemia type II, with ocular signs and symptoms.

METHODS

Participants included nine patients (18 eyes) who were followed for a mean follow-up period of 6.5 years (range, 2 to 8 years). Intervention included dietary restriction of tyrosine and phenylalanine, which led to resolution of ocular and cutaneous lesions, improved behavior in one patient, and may have prevented developmental delay in others. The main outcome measures were visual acuity and serum tyrosine levels to determine the response to dietary therapy. Intelligence testing and developmental screening were performed when appropriate.

RESULTS

All patients presented with ocular signs and symptoms as the primary manifestation of disease and serve to illustrate the typical ocular findings of this syndrome. Three patients presented with cutaneous manifestations, and one patient had mild mental impairment at the time of diagnosis.

CONCLUSIONS

Recalcitrant pseudodendritic keratitis may be the presenting sign in tyrosinemia type II. Awareness of the presenting signs and symptoms may accelerate the diagnosis and dietary intervention. Initiation of a tyrosine-restricted and phenylalanine-restricted diet in infancy is most effective in preventing cognitive impairment.

Richner-Hanhart syndrome (tyrosinemia type II). Case report and literature review

Richner-Hanhart syndrome (Tyrosinemia Type II) is an autosomal recessive disorder of amino acid metabolism characterized by ocular changes, painful palmoplantar hyperkeratosis, and mental retardation. Serum tyrosine increases due to tyrosine aminotransferase deficiency resulting in the deposition of tyrosine crystals in the cornea and in corneal inflammation. Patients are often misdiagnosed as having herpes simplex keratitis. We report on a child who presented with bilateral keratitis secondary to Tyrosinemia Type II diagnosed as herpes simplex keratitis.

Hereditary tyrosinaemia type II in a consanguineous Ashkenazi Jewish family: intrafamilial variation in phenotype; absence of parental phenotype effects on the fetus

We describe an Ashkenazi Jewish family in which two adults, offspring of consanguineous parents, have persistent hypertyrosinaemia (770-1110 mumol/L; normal less than 110 mumol/L). The metabolic disorder in this family is apparently due to hepatic cytosolic tyrosine aminotransferase deficiency (hereditary tyrosinaemia, type II; McKusick, 276600), because it is associated with the oculocutaneous manifestations of Richner-Hanhart syndrome. The association of this syndrome with hereditary tyrosinaemia type II is presumed to be constant. It is not in this family. The affected female sib (age 41 years) has hypertyrosinaemia and oculocutaneous signs; the brother (age 39 years) has hypertyrosinemia but no oculocutaneous disease. Both sibs have two children; none has signs of a metabolic fetopathy. Maternal hypertyrosinaemia and maternal hyperphenylalaninaemia evidently constitute different risk factors for the fetus. Paternal hypertyrosinaemia is apparently not a risk to male infertility.

The effect of diet on the ophthalmological, clinical and biochemical aspects of Richner-Hanhart syndrome: a morphological ultrastructural study of the cornea and the conjunctiva

Type II tyrosinemia (Richner-Hanhart syndrome) is a familial aminoacid disorder, clinically characterized by ocular changes (keratitis), palmo-plantar hyperkeratosis, no constant mental changes with mental deterioration, abnormal urinary excretion and high serum tyrosine level in consequence of the absence of tyrosine-aminotransferase. Almost 20 families have been described in the literature of which 50% are of Italian origin, suggesting that this disorder is particularly frequent in our country. We report a family with 2 affected members with typical clinical and biochemical findings (keratitis, palmo-plantar hyperkeratosis, abnormal urinary and serum tyrosine concentrations), not suffering from mental retardation. Clinical symptoms completely disappeared after the decrease of urinary and serum tyrosine levels following a tyrosine- and phenylalanine-free diet. These cases are compared with those reported in literature, and the usefulness of diet for the improvement of clinical and metabolic symptoms is discussed.

Tyrosinaemia II

Four cases of tyrosinaemia type II (Richner-Hanhart syndrome) are reported. This syndrome consists of corneal erosions, palmar and plantar hyperkeratoses, and sometimes mental retardation. Presentation with photophobia and dendritic corneal ulceration or circumscribed palmoplantar keratoderma should alert the physician to the possible diagnosis of tyrosinaemia II. Early diagnosis is important, as the clinical picture can be modified by dietary restriction.